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I'm trying to make density plots of spherical harmonics. I would like the low valued regions to be transparent. For example in the following plot I want everything but the red and yellow regions to be transparent so that all four such regions are visible.

SliceDensityPlot3D[
Re@SphericalHarmonicY[3, 2, ArcTan[z, Sqrt[x^2 + y^2]], 
 ArcTan[x, y]], "CenterSphere", {x, -2, 2}, {y, -2, 2}, {z, -2, 2}, 
 ColorFunction -> ColorData["TemperatureMap"], Boxed -> False, 
 Axes -> False, PlotPoints -> 200]

enter image description here

Another example:

SphericalPlot3D[1, {\[Theta], 0, \[Pi]}, {\[Phi], 0, 2 \[Pi]}, 
ColorFunction -> 
Function[{x, y, z, \[Theta], \[Phi], r}, 
ColorData["ThermometerColors"][
Re[SphericalHarmonicY[3, 2, \[Theta], \[Phi]]]]], 
ColorFunctionScaling -> False, Mesh -> False, Boxed -> False, 
Axes -> False, PlotPoints -> 200]

enter image description here

Is there a way to get just the white part (in another color) and add transparency to the blue part?

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There is an example in the ColorData documentation under Applications just for this.

Create a new ColorFunction that adds an Opacity directive.

ColorFunction -> (Directive[Opacity[#], 
    ColorData["TemperatureMap"][#]] &)

enter image description here

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  • $\begingroup$ Thank you. This is what I was looking for. It would be nice if the sections of negative values were totally clear and the color gradient was applied to values grater than zero with increasing intensity. $\endgroup$ – Anthony Gaussoin Oct 8 '17 at 17:16
  • $\begingroup$ I admit that this solution is much less hacky than mine =) $\endgroup$ – Henrik Schumacher Oct 8 '17 at 17:35

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